JP2008235765A - Light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device whose mounted device can be reduced in size by making it possible to be thinned further. <P>SOLUTION: The light emitting device includes an insulating substrate 2 through which a through hole 21 is formed, an anode electrode 31 which is formed at one edge of the insulating substrate 2, a cathode electrode 32 which is formed at another edge so as to close the opening of the through hole 21 on the back B, a light-emitting element 4 which is die-bonded on the cathode electrode 32 exposed by the through hole 21, and wires 5a, 5b which are first bonded to the light-emitting element 4 and is second bonded to the anode electrode 31 and cathode electrode 32. The through hole 21 is formed so that the opening area increase expanded, starting from the back B toward the front F, thereby, the surrounding wall surface S is inclined. A plated layer 36 is formed on the inclined surface S. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light emitting device including a light emitting element and a substrate provided with electrodes for supplying power to the light emitting element at both ends.

  Patent Document 1 discloses a light emitting device in which an insulating substrate provided with electrodes at both ends and a light emitting element connected to each electrode are provided.

In the chip component type LED described in Patent Document 1, a metal layer is formed on the surface of an insulating substrate in which a through hole is formed, and a metal thin plate that closes the opening of the through hole is provided on the back surface. One wiring pattern is formed so as to extend to the inclined surface and bottom surface (thin metal plate) of the through hole, and an LED chip is mounted on this wiring pattern.
JP 7-235696 A

  The chip component type LED described in Patent Document 1 is thinned by disposing the LED chip in a recess formed by a wiring pattern formed on a thin metal plate that forms a through hole in an insulating substrate and closes the opening of the through hole. It has been.

  However, the demand for thinning is even higher. For example, cellular phones equipped with light-emitting devices are on the order of several μm for all parts in order to improve portability and design. However, miniaturization is required. Therefore, further thinning is required also in the light emitting device.

  Therefore, an object of the present invention is to provide a light-emitting device that can be reduced in size by enabling further reduction in thickness.

  In the light emitting device of the present invention, an insulating substrate in which a through hole is formed, one electrode formed at one end of the insulating substrate, and an opening of the through hole on the back surface side at the other end. And the light emitting element die-bonded on the other electrode exposed through the through hole.

  In the present invention, since the light emitting element can be mounted at a position as low as the plate thickness of the insulating substrate, the thickness of the entire light emitting device can be reduced. Therefore, by further reducing the thickness, the mounted device can be reduced in size.

  In the first invention of the present application, an insulating substrate in which a through hole is formed, one electrode formed at one end of the insulating substrate, and the opening of the through hole on the back surface side at the other end are blocked. The other electrode formed and the light emitting element die-bonded on the other electrode exposed by the through-hole are provided.

  In the light emitting device of the present invention, since the light emitting element is directly die-bonded to the other electrode formed so as to close the opening of the through hole, the light emitting element is mounted at a position as low as the thickness of the insulating substrate. Can do. Therefore, the thickness of the entire light emitting device can be reduced.

  The second invention of the present application is characterized in that a wire first bonded to the light emitting element and second bonded to one of the electrodes is provided.

  For example, when the wire is wired so as to be first-bonded to one electrode and second-bonded to the light-emitting element, contrary to the light-emitting device of the present invention, the wire is raised vertically from the upper surface of the insulating substrate. In the light-emitting device of the present invention, the wire is first bonded to the light-emitting element to raise the wire vertically, and the wire is extended in a bow shape and is second-bonded to one electrode. Therefore, even if the wire is raised vertically from the first bonded light emitting element, the position where the light emitting element is mounted by the thickness of the insulating substrate is die-bonded to the other electrode that closes the opening of the through hole. Since it is lower, the wiring height can be made lower than when first bonding to one electrode. Therefore, the thickness of the light emitting device can be further reduced.

  According to a third invention of the present application, the insulating substrate is characterized in that a plating layer is formed on the peripheral wall surface of the through hole.

  The peripheral wall surface of the through hole provided in the insulating substrate receives light from the side surface of the light emitting element. By forming a plating layer on the peripheral wall surface, the received light can be reflected, and the luminance can be improved. Further, since the plating layer is provided on the peripheral wall surface, it does not affect the increase in the thickness of the entire light emitting device.

(Embodiment)
A light emitting device according to an embodiment of the present invention will be described with reference to the drawings. First, the structure of the light emitting device according to the present embodiment will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing a light emitting device according to an embodiment of the present invention. FIG. 2 is a plan view of the light-emitting device shown in FIG. FIG. 3 is a bottom view of the light-emitting device shown in FIG.

  As shown in FIGS. 1 to 3, the light emitting device 1 includes an insulating substrate 2, an electrode 3, a light emitting element 4 formed of a semiconductor, wires 5 a and 5 b that are thin metal wires, and a sealing formed of a resin. A stop portion 6 and a resist film 7 are provided.

  The light emitting device 1 has a length in the length direction including the electrodes 3 at both ends of about 1.6 mm, a length in the width direction of about 0.8 mm, and a thickness from the resist film 7 to the sealing portion 6 of 0.2 mm. Is formed.

  The insulating substrate 2 is formed of a glass epoxy resin or BT resin having a thickness of 0.06 mm, and a through hole 21 is provided at the center. The through-hole 21 is formed so that the opening on the back surface B side of the insulating substrate 2 is about 0.43 mm and the opening area gradually increases from the back surface B side to the front surface F side. Has an inclined surface of about 45 ° with respect to the horizontal. This inclined surface functions as a reflective surface by being provided with a plating layer such as silver plating.

  The electrode 3 is formed in a wiring pattern having a thickness of about 23.5 μm, and an anode electrode 31 is provided at one end in the longitudinal direction of the insulating substrate 2 and a cathode electrode 32 is provided at the other end. The anode electrode 31 and the cathode electrode 32 are formed from the front surface F to the back surface B, so that the vertical cross section is formed in a substantially U shape. The cathode electrode 32 is formed so as to close the opening of the through hole 21 on the back surface B. The electrode 3 is provided with a wire bonding wiring pattern 33 in a substantially L shape at the inner position of each of the anode electrode 31 and the cathode electrode 32, and a tip portion is a bonding portion 33a to be wire bonded. . A resist film 34 for preventing resin leakage when the mold is clamped to form the sealing portion 6 is formed at the base end portion of the wire bonding wiring pattern 33.

  The light emitting element 4 is, for example, a blue light emitting element in which an n layer, a light emitting layer, and a p layer that are semiconductor layers are stacked on a sapphire substrate that is an insulating substrate. In the light emitting element 4, an n electrode is provided as a bonding electrode in a p layer, a region formed by etching the light emitting layer and a part of the n layer, and a p electrode is provided in the p layer as a bonding electrode. The light emitting element 4 is die-bonded on the cathode electrode 32 with a conductive adhesive 41 such as silver paste interposed therebetween.

  The wire 5a is wired from the p electrode of the light emitting element 4 to the bonding portion 33a of the wire bonding wiring pattern 33 on the anode electrode 31 side, and the wire 5b is bonded to the wire bonding wiring pattern 33 on the cathode electrode 32 side from the n electrode. It is wired to the part 33a.

  The sealing part 6 is formed of an epoxy resin. The sealing portion 6 may contain a phosphor that emits a complementary color by converting the wavelength of light from the light emitting element 4. In the present embodiment, since the light emitting element 4 emits blue light, if the phosphor that converts the wavelength to yellow is used, the surface of the sealing portion 6 is wavelength-converted to blue from the light emitting element 4. Yellow can be mixed to emit white light.

  The resist film 7 is provided for the purpose of preventing a short circuit between the anode electrode 31 and the cathode electrode 32 and displaying the polarity.

  A method of manufacturing the light emitting device according to the embodiment of the present invention configured as described above will be described with reference to FIGS. 4A and 4B are diagrams showing an insulating substrate on which an electrode is formed. FIG. 4A is a plan view, FIG. 4B is a bottom view, and FIG. 4C is a cross-sectional view. 5A and 5B are diagrams showing an insulating substrate provided with through holes, where FIG. 5A is a plan view and FIG. 5B is a cross-sectional view. 6A and 6B are diagrams showing an insulating substrate provided with a resist film, where FIG. 6A is a plan view, FIG. 6B is a bottom view, and FIG. 6C is a cross-sectional view. FIG. 7 is a cross-sectional view showing an insulating substrate on which a plating layer is formed. 8A and 8B are diagrams illustrating an insulating substrate on which a light-emitting element is mounted and wires are wired. FIG. 8A is a plan view and FIG. 8B is a cross-sectional view.

  First, a substrate forming process is performed. In the substrate forming step, the insulating substrate material with the copper foil formed on the entire surface is etched, and as shown in FIGS. 4A to 4C, the anode electrode 31 and the both ends of the insulating substrate 2, An electrode 3 having a cathode electrode 32 and a wire bonding wiring pattern 33 connected to each of them is formed.

  Next, as shown in FIGS. 5A and 5B, a through hole 21 is formed in the central portion of the insulating substrate 2 by a drill, a mold, laser light, or the like. The through-hole 21 penetrates only the insulating substrate 2 and exposes the cathode electrode 32 from the surface F side. When forming the through-hole 21, it drills so that the surrounding wall surface S may become an inclined surface. By forming the through-hole 21, a recess 22 is formed in which the cathode electrode 32 is a bottom surface and the insulating substrate 2 is a peripheral wall surface.

  6A to 6C, a semicircular resist film 34 is formed on the base end portion of the wire bonding wiring pattern 33 on the front surface F side, and the anode electrode 31 on the back surface B side. A substantially home-base resist film 7 is formed at a position straddling the cathode electrode 32.

  Then, as shown in FIG. 7, nickel plating and gold plating are performed on the electrode 3 excluding the portions covered with the resist films 34 and 7, and silver plating is performed on the peripheral wall surface (inclined surface) S, thereby plating layers 35 and 36. Form. By forming the plating layer 36 on the peripheral wall surface S, the light emitted from the light emitting element 4 to the side can be reflected by the plating layer 36, so that the luminance can be improved.

  Following the substrate forming step, a mounting step for mounting the light emitting element 4 is performed. In the mounting process, as shown in FIGS. 8A and 8B, the light emitting element 4 is die-bonded with the conductive adhesive 41 interposed in the recess 22 having the cathode electrode 32 as the bottom surface. By directly mounting the light emitting element 4 on the cathode electrode 32, which is the bottom surface of the recess 22, the light emitting element 4 can be mounted at a position lower by the plate thickness of the insulating substrate 2.

  When the mounting process is completed, a wiring process is performed next. In the wiring process, as shown in FIGS. 8A and 8B, wires 5a and 5b are wired. The wire 5a is formed by first bonding to the p electrode of the light emitting element 4 and second bonding to the bonding portion 33a on the anode electrode 31 side. The wire 5b is formed by first bonding to the n electrode and second bonding to the bonding portion 33a on the cathode electrode 32 side. When wiring the wires 5a and 5b, after first bonding to the light emitting element 4, the wires 5a and 5b are raised while being vertically extended, and then the wires 5a and 5b are extended in a bow in the connecting direction to form the electrode 3 (anode electrode 31, A second bond is made to the cathode electrode 32). Accordingly, since the position where the light emitting element 4 is mounted becomes lower by the thickness of the insulating substrate 2, the wiring height can be lowered even if the wire is stretched as it is after the first bond and then the wire is raised vertically. it can.

  When the wiring process is completed, a sealing process is performed next. In the sealing step, the light-emitting element 4 is die-bonded, and the insulating substrate 2 that has been wire-bonded is clamped with a mold having a cavity for forming the sealing portion 6 and filled with resin to form the sealing portion 6. To do. By forming the sealing portion 6, the light emitting device 1 as shown in FIGS. 1 to 3 is obtained.

  Even if the resin is pressed into the recess 22, the light-emitting element 4 does not move in the recess 22 because the conductive adhesive 41 fixes the light-emitting element 4. Since the sealing part 6 can suppress the wiring height of the wires 5a and 5b to be low, the protective function of the light emitting element 4 and the wires 5a and 5b is not impaired even if the thickness is formed thin. Therefore, the thickness of the entire light emitting device 1 can be reduced by die-bonding the light emitting element 4 directly to the recess 22 having the cathode electrode 32 as a bottom surface.

  As described above, since the entire thickness of the light emitting device 1 can be reduced, for example, it can contribute to downsizing of a mobile phone or the like.

  Next, a light emitting device according to another embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a cross-sectional view showing a light emitting device according to another embodiment of the present invention. FIG. 10 is a plan view of the light-emitting device shown in FIG. FIG. 11 is a bottom view of the light-emitting device shown in FIG. 9 to 11, the same components as those shown in FIGS. 1 to 3 are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIGS. 9 to 11, a light emitting device 10 according to another embodiment of the present invention employs a light emitting element 11 that is conductively connected to an n electrode by die bonding to a cathode electrode 32. .

  In the light-emitting element 11, an n-layer, a light-emitting layer, and a p-layer that are semiconductor layers are stacked on a GaN substrate that is a conductive substrate, and a p-electrode is opposite to the side on which the semiconductor layer is stacked on the p-layer. An n-electrode is formed on the back side of the substrate. Accordingly, the p electrode is conductively connected to the anode electrode 31 by the wire 5a, and the n electrode is conductively connected by die bonding to the cathode electrode 32. Therefore, the wire 5b as shown in FIGS. 1 and 2 can be omitted.

  Thus, since the light emitting device 10 can be conductively connected to the n electrode by die-bonding the light emitting element 11 to the cathode electrode 32, a new wiring pattern is provided on the insulating substrate 2 or a new wire is provided. There is no need.

  The electrode 3 is formed so that the cathode electrode 32 closes the opening of the through-hole 21 on the back surface B side, and the wiring pattern 33 for wire bonding is connected, so that the light-emitting device 1 shown in FIGS. Even in the light emitting device 10 shown in FIGS. 9 to 11, the insulating substrate 2 on which the electrodes 3 are formed can be used in common.

  According to the present invention, since the device to be mounted can be reduced in size by enabling further reduction in thickness, the device includes a light emitting element and a substrate provided with electrodes for supplying power to the light emitting element at both ends. Suitable for light emitting devices.

Sectional drawing which shows the light-emitting device which concerns on embodiment of this invention FIG. 1 is a plan view of the light emitting device shown in FIG. Bottom view of the light emitting device shown in FIG. It is a figure which shows the insulated substrate in which the electrode was formed, (A) is a top view, (B) is a bottom view, (C) is sectional drawing. It is a figure which shows the insulated substrate which provided the through-hole, (A) is a top view, (B) is sectional drawing. It is a figure which shows the insulated substrate which provided the resist film, (A) is a top view, (B) is a bottom view, (C) is sectional drawing. Sectional view showing an insulating substrate on which a plating layer is formed It is a figure which shows the insulated substrate with which the light emitting element was mounted and the wire was wired, (A) is a top view, (B) is sectional drawing. Sectional drawing which shows the light-emitting device which concerns on other embodiment of this invention. FIG. 9 is a plan view of the light emitting device shown in FIG. 9 is a bottom view of the light emitting device shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light-emitting device 2 Insulating substrate 3 Electrode 4 Light-emitting element 5a, 5b Wire 6 Sealing part 7 Resist film 10 Light-emitting device 11 Light-emitting element 21 Through-hole 22 Recessed part 31 Anode electrode 32 Cathode electrode 33 Wire bonding wiring pattern 33a Bonding part 34 Resist Films 35 and 36 Plating layer 41 Conductive adhesive B Back surface F Surface S Circumferential wall surface

Claims (3)

An insulating substrate having a through hole;
One electrode formed on one end of the insulating substrate, and the other electrode formed on the other end so as to close the opening of the through hole on the back surface side;
A light emitting device comprising: a light emitting element die-bonded on the other electrode exposed through the through hole. The light emitting device according to claim 1, further comprising a wire that is first bonded to the light emitting element and second bonded to the one electrode. The light emitting device according to claim 1, wherein the insulating substrate has a plating layer formed on a peripheral wall surface of the through hole.

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